Nocturnal Polyuria Calculator - Calculate Nighttime Urine Output

Nocturia is one of the most elusive symptoms to treat. It affects over 50% of men and women aged over 60 years. In nocturnal polyuria there is an increased production of urine during the night-time compared with the 24 hour urine volume (1^✔).

What is Nocturnal Polyuria?

Nocturnal polyuria, also known as nocturia, is a condition characterized by excessive urination at night. About 1 in 3 adults over the age of 30 experience nocturia. Nocturnal polyuria causes include disturbance in the hormone arginine vasopressin (AVP) or antidiuretic hormone (ADH) secretion from the pituitary gland in the brain, especially during the night.

Vasopressin and Nocturnal Polyuria: Normally vasopressin increases water absorption within the kidneys and a lack of it causes increase in the urine volume. In nocturnal polyuria there is a decreased excretion of vasopressin in night by the pituitary gland.

Diabetes Insipidus and ADH or Vasopressin: In patients with diabetes insipidus, there is a general deficiency of the hormone ADH or vasopressin.

Nocturnal polyuria can also occur due to other causes like heart failure and sleep apnea. Sometimes it is caused by taking certain medications (Example- taking diuretics in the evenings or night), consuming caffeine, alcohol or even excess intake of water in the evening or night.

In diabetes mellitus and diabetes insipidus there is polyuria both in the day and night. In nocturnal polyuria, the 24-hour urine output (diuresis) is normal or only slightly increased, but the shift of diuresis from daytime to night time disrupts the night sleep quality at night. This causes tiredness during the day and decreases, not only work the person's work efficiency of the person but also makes them prone to accidents(2^✔).

What is Nocturnal Polyuria Index (NPi)?

The International Continence Society specifically defines nocturnal polyuria as Nocturnal Polyuria Index (NPi). It takes into account the percentage of night time urine volume based on a person's age:

• In elderly individuals (≥65 years), nocturnal polyuria is defined as nighttime urine volume accounting for approximately 33% or more of the total 24-hour urine output.
• In younger individuals, it is typically diagnosed when nighttime urine output exceeds 20% of the total daily volume.
• For middle-aged individuals, nocturnal polyuria is characterized by a nighttime urine output ranging between 20% and 33% of the total 24-hour urine production.

What is a Voiding Diary?

Download & Print Voiding Diary

A frequency volume chart or a voiding diary measures fluid intake and urine output of a person including the urination frequency during a 24 hour period. Nocturnal urine volume is the amount of urine a person excretes at night. This calculation helps doctors to understand the fluid input and output, the resulting frequency and the volume of urine passed. It normally should be completed over 3 to 5 consecutive days to diagnose the problem.

The main columns in a voiding diary should be completed with the recorded time. Additional information, such as symptoms of urgency or urine leakage due to urgency, can also be noted.

Fluid Intake: This is the total amount of fluids consumed (Milliliters or Ounces) during a 24 hour period.

Time of Day: Every time you pass urine, mark the time next to the appropriate hour time slot.

Toilet Voids or Urine output: This is the volume of urine voided each time during the day or the night. Every time you pass urine measure the amount in a measuring jar and record the volume (in Milliliters or Ounces).

Leakage or wetness: Put a check mark in the 'wet' column if or involuntary urine loss occurs (even if it is a small amount) before you reach the toilet (3^✔). To keep a daily account download Medindia's Voiding Diary
Download Voiding Diary Form

What are the Tips to Control Nocturnal Polyuria?

• Limiting fluid intake 6 hours before sleep time results in a decreased amount of urine produced at night.
• Reducing caffeine and alcohol intake
• Afternoon naps can help reduce fluid build up by allowing liquid to be absorbed in the bloodstream.
• Elevating your legs helps redistribute fluids so it can be reabsorbed into the blood stream.
• Compression stockingsalso create a similar effect as these elastic stockings exert pressure against the leg while decreasing pressure on the veins. Hence, fluids are redistributed and reabsorbed into the bloodstream.

The best sleeping position for nocturia is with a small pillow under the knees. Sleeping on the left side or semi-fetal position may also help with the condition.

How to manage Nocturnal Polyuria?

Supportive Measures

• Usage of mattress covers that are absorbing and made of waterproof vinyl material or sheet protectors. This will help to make the cleaning up easier.
• Absorbent briefs are a form of modified underwear designed to absorb liquid to prevent leakage.
• Skincare products such as soaps, lotions and cleansing clothes are available to protect the skin from irritation and soreness that can occur due to urine being in contact with skin for long duration(4^✔).

Medications for the Treatment of Nocturnal Polyuria

Pharmacologic options, including tablets, may be used alone or in combination with behavioral modifications. This approach has been shown enhanced effectiveness.

The nocturnal bladder capacity (healthy bladder capacity) is about 300 to 400 milliliters of urine at night. A reduced bladder capacity can lead to more frequent urination.

Anticholineric agents like Darifenacin, Oxybutynin, Tolterodine, Trospium Chloride and Solifenacin are first line drug therapy. They reduce the symptoms of an overactive bladder. If they are ineffective other options can be looked into.

Desmopressinmimics ADH and thus the kidney produces less urine.

Imipramine, a tricyclic antidepressant works by shortening the sleep stage where bed wetting occurs.

Melatonin can restore a normal circadian rhythm of elimination of urine and improve sleep.

Surgery is an option if the cause of nocturia is related to the obstruction of the prostate or an overactive bladder. However the results are not predictable.

Nocturnal polyuria can be a debilitating problem for those affected by it, as it causes chronic sleep impairment. Proper management, treatment, and encouragement are needed to help the patients lead a better quality of life (5^✔).

What is Sacral neuromodulation?

This is the last resort in treating refractory conditions like urge incontinence along with Nocturnal Polyuria. It involves inserting an implantable device in the sacral region that stimulates the third sacral nerve. It reduces urgency and the total number of voids, with success rates approaching 85% for controlling urgency, urge incontinence, and nocturia after one year. This is an expensive procedure and requires a well trained urologist to conduct it(6^✔).

What is the Economic Impact of Nocturia?

• Nocturia‐related falls in bathrooms and hip fractures cost approximately �1 billion in the EU and $1.5 billion in the USA in 2014.
• The economic impact of nocturia on society is costly with direct costs related to treatment estimated to be ≥1.5 billion/year.
• Indirect costs of decreased work productivity, poor concentration, and increased time away from work are estimated to be up to ≥61 billion/year(13^✔,14^✔).

Interesting Facts about Nocturnal Polyuria

• Nocturnal polyuria increases with age.
• It is equally present in men and women.
• There is higher prevalence in younger women than younger men and older men than older women.
• Studies show that urinating at least twice a night occurs in
  - 5-15% of people who are 20-50 years old
  -20-30% of people who are 50-70 years old
  -10-50% of people 70+ years old
• Many communities have reported more than 50 percent of men and women over the age of 60 have nocturia. Even more over the age of 80 are shown to experience symptoms of nocturia regularly.